Diatom-inferred pH calibration of lakes near Wawa, Ontario

1986 ◽  
Vol 64 (6) ◽  
pp. 1129-1133 ◽  
Author(s):  
Sushil S. Dixit
Keyword(s):  
Multiple Regression ◽  
Surface Sediment ◽  
Lake Water ◽  
Ph Indicator ◽  
Lake Region ◽  
Water Ph ◽  
Sedimentary Diatoms ◽  
Inferred Ph ◽  
Ph Calibration

In the absence of long-term pH records for lakes, sedimentary diatoms have often been used to detect the extent of recent lake acidification. Although various methods have been used to relate surface-sediment diatom remains to contemporary lake-water pH, their usefulness and selection criteria have not been clearly defined for Canadian lakes. Surface-sediment diatoms of 28 lakes (pH 4.0–8.13) located northeast of Lake Superior were identified and enumerated. Lake-water pH estimates were made using multiple regression analyses of selected diatom taxa and Hustedt's pH indicator groups, as well as by index α and index B. Multiple regression, using the abundance of pH indicator assemblages, appears to be the most suitable method for the studied lake region. Discrepancies associated with other methods are discussed in details.

Surface-sediment chrysophytes from 35 Quebec lakes and their usefulness in reconstructing lake-water pH

1989 ◽  
Vol 67 (7) ◽  
pp. 2071-2076 ◽  
Author(s):  
Aruna S. Dixit ◽  
Sushil S. Dixit
Keyword(s):  
Surface Sediment ◽  
Lake Water ◽  
Predictive Ability ◽  
Strong Relationship ◽  
Ph Indicator ◽  
Ph Values ◽  
Water Ph ◽  
History Of ◽  
Inferred Ph ◽  
Water Acidity

Chrysophyte scales from surface sediment samples of 35 Quebec lakes were analyzed to examine their relationship with lake-water pH. The percent composition of common chrysophyte taxa were plotted against the measured lake-water pH. The distribution of many taxa was found to be closely associated with pH. The pH indicator status and abundance-weighted mean pH values of the majority of taxa of the studied region agreed with the published work. Chrysophyte counts were quantified to establish a predictive pH model using multiple regressions of pH indicator chrysophyte assemblages with lake-water pH. A strong relationship (r2 = 0.72) was observed between measured and inferred pH values. The pH predictive ability of chrysophytes was further corroborated by reconstructing the recent pH history of Lake Bonneville. Over the last 30 years, the inferred pH of this lake has declined ≈ 1 pH unit. The present study accentuates that stratigraphic analysis of chrysophytes will provide useful measurements of the extent of lake-water acidity in Quebec.

Scaled Chrysophytes (Chrysophyceae) as Indicators of pH in Sudbury, Ontario, Lakes

1988 ◽  
Vol 45 (8) ◽  
pp. 1411-1421 ◽  
Author(s):  
Sushil S. Dixit ◽  
Aruna S. Dixit ◽  
R. Douglas Evans
Keyword(s):  
Lake Water ◽  
Ph Indicator ◽  
Related Factors ◽  
Scaled Chrysophytes ◽  
Calibration Equation ◽  
Water Ph ◽  
History Of ◽  
Inferred Ph ◽  
Relationship Of ◽  
The Relationship

Surface sediment chrysophytes (Chrysophyceae) of 30 Sudbury, Ontario, lakes were analyzed to investigate the relationship of these algal microfossils with the limnological characteristics of the study lakes. The distribution of the majority of common chrysophyte taxa is correlated closely with lake water pH, pH-related factors, or both. Chrysodidymus synuroideus, Synura echinulata, Mallomonas hamata, M. acaroides var. muskokana, and Chrysosphaerella longispina appear to be indicators of strongly to moderately acidic waters whereas M. pseudocoronata and M. caudata are indicators of circumneutral to alkaline waters. Using multiple regression of pH indicator chrysophyte assemblages against the measured lake pH, a calibration equation was developed to compute chrysophyte-inferred pH. Chrysophyte-inferred pH values were closely related with measured lake water pH (r2 = 0.74). The study indicates that in the absence of historical pH data, stratigraphic analysis of scaled chrysophytes would provide useful information about the history of lake acidification in the Sudbury area. There is some indication that high metal concentrations, in addition to pH, may influence chrysophycean species distribution in acidic lakes.

Assessment of Changes in Lake Water Chemistry in Sudbury Area Lakes since Preindustrial Times

1992 ◽  
Vol 49 (S1) ◽  
pp. 8-16 ◽  
Author(s):  
Sushil S. Dixit ◽  
Aruna S. Dixit ◽  
John P. Smol
Keyword(s):  
Lake Water ◽  
Acidic Ph ◽  
Prevailing Wind ◽  
Alkaline Ph ◽  
Sediment Samples ◽  
Ion Concentrations ◽  
The Past ◽  
Lake Water Chemistry ◽  
Water Ph ◽  
Inferred Ph

Surface (recent) and bottom (pre-1880s) sediment samples from each of 72 Sudbury area lakes were analyzed for diatom valves and chrysophyte scales, and using these microfossils, we inferred changes in lake water pH, [Al], [Ni], conductance, and [Ca]. The study shows that extensive acidification has occurred in presently acidic (pH < 6.0) Sudbury lakes. Inferred [Al] has also increased in these lakes. The region also contains a few naturally acidic lakes; however, even these lakes have acidified further since the bottom sediments were deposited. Lakes that have current measured pH between 6.0 and 7.0 have either declined or increased in inferred pH in the past, whereas all lakes that are presently alkaline (pH > 7.0) have become more alkaline. The increase in inferred [Ni] in most of the study lakes indicates that Ni inputs are mainly atmospheric. Our data suggest that, in general, ion concentrations have increased in Sudbury lakes. The extent of acidification or alkalification in Sudbury lakes was primarily a function of proximity of the lakes to the smelters, orientation of prevailing wind patterns, and differences in watershed geology.

Correlation of surface sediment diatoms with the present lake water pH in 28 Algoma lakes, Ontario, Canada

Hydrobiologia ◽  
1986 ◽  
Vol 131 (2) ◽  
pp. 133-143 ◽  
Author(s):  
Sushil S. Dixit ◽  
Mike D. Dickman
Keyword(s):  
Surface Sediment ◽  
Lake Water ◽  
Water Ph

Attempts to reconstruct lake water pH and colour from sedimentary diatoms and Cladocera

1988 ◽  
Vol 23 (2) ◽  
pp. 870-873
Author(s):  
P. Huttunen ◽  
J. Merilälnen ◽  
C. Cotten ◽  
J. Rönkkö
Keyword(s):  
Lake Water ◽  
Water Ph ◽  
Sedimentary Diatoms

Relationship between Chrysophyte Assemblages and Environmental Variables in Seventy-Two Sudbury Lakes as Examined by Canonical Correspondence Analysis (CCA)

1989 ◽  
Vol 46 (10) ◽  
pp. 1667-1676 ◽  
Author(s):  
Sushil S. Dixit ◽  
Aruna S. Dixit ◽  
John P. Smol
Keyword(s):  
Correspondence Analysis ◽  
Canonical Correspondence Analysis ◽  
Surface Sediment ◽  
Important Variable ◽  
Great Promise ◽  
Calibration Model ◽  
Ph Indicator ◽  
History Of ◽  
Inferred Ph ◽  
Almost All

Relationship between surface sediment chrysophyte scales and limnological variables in 72 Sudbury lakes was examined using canonical correspondence analysis (CCA). CCA is a recently developed multivariate direct gradient analysis that has many advantages over indirect gradient analyses. Lakewater pH was identified as the most important variable influencing the distribution of scaled chrysophytes in Sudbury lakes. Almost all common chrysophyte taxa can be assigned a pH indicator value. In addition to pH, many chrysophyte taxa are sensitive to metal concentrations. A calibration model was developed to predict chrysophyte inferred pH using CCA. The model proved to be far superior to traditionally used models derived from multiple regression of pH indicator chyrsophyte assemblages. Applicability of the predictive pH equation was examined by reconstructing the recent pH history of Lohi Lake. The study provides compelling evidence that canonical correspondence analysis offers great promise in surface sediment calibration and pH reconstruction studies.

Long-Term Trends in Lake Water pH and Metal Concentrations Inferred from Diatoms and Chrysophytes in Three Lakes near Sudbury, Ontario

1992 ◽  
Vol 49 (S1) ◽  
pp. 17-24 ◽  
Author(s):  
Aruna S. Dixit ◽  
Sushil S. Dixit ◽  
John P. Smol
Keyword(s):  
Lake Water ◽  
Sediment Cores ◽  
Chemical Recovery ◽  
Metal Concentrations ◽  
Acid Lakes ◽  
Water Ph ◽  
Long Term Trends ◽  
The 1960S ◽  
Provincial Park

Diatom valves and chrysophyte scales were analyzed in sediment cores to assess historical (post-1860) and recent (since 1970) trends in lake water pH, total [Al], and [Ni] in Lumsden, George, and Acid lakes (Killarney Provincial Park, Ontario). Although acidification in Lumsden and Acid lakes started in the 1930s, rapid acidification only occurred since the 1960s. As lake water pH declined, inferred [Al] greatly increased causing the extirpation of the sport fisheries. In nearby George Lake, acidification started in the 1920s, and inferred lake water pH declined about 0.5 of a pH unit by 1960. The fish community in George Lake survived where the inferred acidification was less severe than Acid and Lumsden lakes. As in previous paleolimnological studies, chrysophytes generally indicate earlier and more marked acidification trajectories when compared with trends inferred from diatoms, probably because the vernal blooming and euplanktonic chrysophytes are tracking spring pH depressions. Although all three lakes have acidified and metal concentrations have increased during this century, our study provides evidence that these lakes, located as far as 60 km away from Sudbury, are showing signs of biological and chemical recovery as a result of recent reductions in SO2 emissions from the Sudbury smelters.

scholarly journals A new diatom training set for the reconstruction of past water pH in the Tatra Mountain lakes

2021 ◽  
Author(s):  
Elwira Sienkiewicz ◽  
Michał Gąsiorowski ◽  
Ladislav Hamerlík ◽  
Peter Bitušík ◽  
Joanna Stańczak
Keyword(s):  
Surface Sediments ◽  
Tatra Mountains ◽  
Training Set ◽  
Statistical Parameters ◽  
The Past ◽  
Water Ph ◽  
Inferred Ph ◽  
The 1960S ◽  
The Tatra Mountains ◽  
The Relationship

AbstractLakes located in the Polish and Slovak parts of the Tatra Mountains were included in the Tatra diatom database (POL_SLOV training set). The relationship between the diatoms and the water chemistry in the surface sediments of 33 lakes was the basis for the statistical and numerical techniques for quantitative pH reconstruction. The reconstruction of the past water pH was performed using the alpine (AL:PE) and POL_SLOV training sets to compare the reliability of the databases for the Tatra lakes. The results showed that the POL_SLOV training set had better statistical parameters (R2 higher by 0.16, RMSE and max. bias lower by 0.2 and 0.36, respectively) compared to the AL:PE training set. The better performance of the POL_SLOV training set is particularly visible in the case of Przedni Staw Polski where the curve of the inferred water pH shows an opposite trend for the period from the 1960s to 1990 compared to that based on the AL:PE dataset. The reliability of the inferred pH was confirmed by the comparison with current instrumental measurements.

Application of OLI Electrolyte Simulation to the Resolution of Corrosion Concerns Within a Reciprocating Compressor

2012 ◽  
Author(s):  
Diane L. Stewart ◽  
Anthony J. Gerbino ◽  
Tony Scribner
Keyword(s):  
Simulation Software ◽  
Dew Point ◽  
Reciprocating Compressor ◽  
Particulate Contamination ◽  
Ionic Equilibria ◽  
Water Ph ◽  
Condensed Water ◽  
Compressor Reliability

A 38 MMSCF/D Cooper Bessemer Model LM-9 reciprocating compressor in hydrogen service at the Praxair Westlake LA facility has experienced notable particulate contamination within the feed gas. The particulates were believed to be caused by upstream piping corrosion; however, to definitely state the cause, the properties of the fluid existing in the five-stage compressor needed to be more fully understood. An OLI electrochemical simulation software was used for dew point prediction, determination of the condensed phase ionic equilibria, and corrosion rate prediction. These tasks were beyond capabilities of the site-licensed UniSim software, as presently configured. Specifically, the model was used to identify the dew point conditions (temperature, pressure) and properties of the condensed water (pH, corrosivity, dissolved O2, and chlorine speciation). Model results were compared with site inspection findings. Subsequently, recommended limits for chlorine and oxygen in the feed gas were established to improve long term compressor reliability.

scholarly journals A method for reconstructing past lake water phosphorus concentrations using sediment geochemical records

2021 ◽  
Author(s):  
Madeleine Moyle ◽  
John F. Boyle
Keyword(s):  
Lake Water ◽  
Water Quality Monitoring ◽  
Specific Reference ◽  
Site Specific ◽  
Burial Rate ◽  
Steady State Model ◽  
Sediment Records ◽  
Current Water ◽  
Study Sites

AbstractAn existing steady state model of lake phosphorus (P) budgets has been adapted to allow reconstruction of long-term average historic lake water total phosphorus (TP) concentrations using lake sediment records of P burial. This model can be applied without site-specific parameterisation, thus potentially having universal application. In principle, it is applicable at any site where there is both a sediment P burial record and knowledge of the current water budget, although we advise caution applying it to problematic sediment records. Tested at six published case study sites, modelled lake water TP concentrations agree well with water-quality monitoring data, and limited testing finds good agreement with wholly independent diatom inferred lake water TP. Our findings, together with a review of the literature, suggest that well preserved lake sediments can usefully record a long-term average P burial rate from which the long-term mean lake water TP can be reliably estimated. These lake water TP reconstructions can provide meaningful site-specific reference values to support decision making in lake eutrophication management, including establishing targets for lake restoration.

Sign in / Sign up

Export Citation Format

Share Document